This invention relates to apparatus for and to a method of smoking meat, fish, cheese, and other edible products using a shower of liquid smoke thus resulting in a faster and more efficient smoking process.
Generally, the smoking of meat products and the like has long been used for preservation and flavoring of the meat products, including link sausages, hot dogs, frankfurters, hams and the like. Smoking has long been used as a preservative, and is known to have an antibacterial effect. Additionally, smoking causes a coagulation of meat protein on the surface of the meat which results in the formation of a skin on the meat and causes a pleasing coloring and flavoring effect.
Traditionally, smoking was carried out in a smoke house in which the meat was hung from the ceiling or from racks, and a slow-burning wood fire was kept lit for a considerable period of time so as to slowly cook and to cure the meat. In prior commercial meat processing plants, wood smoke was produced by regulating the burning of selected types of moist sawdust, or by restricting the oxygen supplied to the burning sawdust. In other instances, a steel friction wheel would rub on a hardwood log so as to produce smoke by friction. It was found that heating sawdust with electric heating elements or the like resulted in a burned odor or flavor being imparted to the smoked products. In more modern commercial smoking operations, smoking apparatus was used which electrostatically precipitated the smoke particles on the meat or other edible products, one such electrostatic smoking apparatus is shown in U.S. Pat. No. 3,106,884.
Wood smoke includes three primary types of compounds, viz, acids, phenols, and carbonyls. It has been found that the acid smoke compounds accelerate curing, form the skin, and contribute a tart flavor to a smoked meat product. Further, it is believed that the phenols result in the smoked color and flavor of the meat products. Lastly, the carbonyls' major contribution is in the smokey coloring of the smoked edible products.
In more recent years, several natural wood smoke aqueous preparations, referred to generally as liquid smoke, have become commercially available and are approved by the U.S. Department of Agriculture. These liquid smoke products have been widely used to "smoke" a variety of meat, fish, oheese, and other edible products. Generally, liquid smoke is applied to the edible products either by directly mixing the liquid smoke with the edible food product (or by direct application to the interior of the casing enclosing the meat product), or by surface application as by spraying a fine mist of the liquid smoke on the exterior of the meat product. Generally, the present invention relates to a surface application method, and thus the direct mixing of the liquid smoke with the ingredients of the edible product will not herein be discussed.
Linked sausage-like products, including linked sausages, hot dogs, frankfurters and the like, are usually formed by stuffing an emulsion of ground meat, spices, and curing agents into a tubular cellulose or collagen casing. The stuffed casing is then compressed and tied-off at equal intervals so as to form a continuous linked sausage-like product. This linking operation is typically carried out on a linking machine such as is shown in U.S. Pat. Nos. 3,115,668, 3,191,222, 3,672,001, 3,694,853, 3,835,503, and 3,873,744. Such machines are commercially available from the Townsend Engineering Company of Des Moines, Iowa, under the tradename Frank-A-Matic. Such linking machines discharge a continuous line of linked sausage products which are then fed onto a chain conveyor having a plurality of spaced J-hooks with loops with the linked sausages suspended from the J-hooks generally in the manner shown in the above-mentioned U.S. Pat. No. 3,672,001. The linked sausages are then manually transferred from this J-hook conveyor to so-called trucks or cages which are then wheeled into a smoke house where either real smoke or liquid smoke is applied. After smoking, the sausages are cooked and chilled prior to being packaged. In certain instances, the smoke house may constitute one portion of a continuous sausage or hot dog processing and manufacturing system. Generally, after the sausages are smoked, cooked, and chilled, it may be necessary to peel the casing from the sausage product. This peeling operation typically is done on a high-speed sausage peeler in which the product is moistened with steam, in which the casing is split, and in which the split casing is removed from the sausage by means of a vacuum, mechanical means, or by compressed air. Because the casing is oftentimes discarded after processing, it is advantageous to utilize the least expensive casings, which are generally cellulose casings. Thus, it is desirable to form a "skin" on the meat product surface below the casing.
Smoke houses utilizing so-called surface-applied liquid smoke processing methods typically utilize a very fine mist or cloud of the liquid smoke which is sprayed on the sausages within the smoke house. Such a misting liquid smoke application method is disclosed in U.S. Pat. No. 3,503,760. While such a misting liquid smoke method worked well for its intended purposes, the atomization of the liquid smoke, using very fine droplets of about 150 microns or less so as to form a cloud of the liquid smoke within the smoke house, required that the edible meat products or the like be moved into the smoke house in batches, the doors of the smoke house closed, the cloud of liquid smoke generated and forcefully circulated over the meat products. However, several minutes were required to atomize the liquid smoke and to fill the smoke house with a cloud of liquid smoke. Then, before the meat products could be removed from the smoke house, it was necessary that the circulation fans within the smoke house be shut off for about 25-30 minutes so as to permit settling of the cloud of liquid smoke before the meat products could be removed from the smoke house. The requirement of batch smoking operations and the necessity of having to shut the fans off for as long as 25 minutes before one completed batch could be exchanged for a batch to be smoked, resulted in inefficiencies of the smoking process and, in some instances, created a bottleneck in the processing of meat products.
Also, since liquid smoke is corrosive, any of the liquid smoke mist escaping from the apparatus must be entrapped by liquid smoke collection apparatus. Further, any materials which come into contact with or are likely to come into contact with the liquid smoke mist must be made of suitable corrosion-resistant materials, such as stainless steel, ceramics or the like. In many instances, however, it was not possible to prevent escaping mist from coming into contact with adjacent equipment, and thus corrosion of the adjacent equipment was experienced.